[hafqa] [hafqa] [Bug 2602] Battery drain low or empty overnight

[From: bugzilla-daemon at maemo.org]

https://bugs.maemo.org/show_bug.cgi?id=2602





------- Comment #34 from eero.tamminen at nokia.com  2008-10-15 18:07 GMT+3 -------
> I don't know the cause (CPU load is low)

Power consumption difference between 100% and 1% CPU usage is probably smaller
than the difference between 1% and no CPU usage.  CPU being able to be shut
down completely saves power much better.

For example application that just wakes up once a second and doesn't do
anything else (like FM-radio applet that stupidly checks whether headset is
connected every second), reduces the idle/offline use-time from a week to one
day. In "top" you see such an app using 0-1% of CPU.

You could disable all the Home and statusbar applets that you don't need (I
think CPU meter statusbar applets for example read /proc/ pretty often and the
banner applet uses network).


> You can see tests here:
> http://www.internettablettalk.com/forums/showthread.php?p=201544#post201544

The lock + press button keeping the screen undimmed could indeed be one factor.
 Could you file a new bug about that and add it as a dependency for this one?


> Note that this battery drain problem appeared with diablo. I added a 8-GB SDHC card at the same time.

Some card models use more power than others, as a rule larger cards use more. 
That should happen only when they're being accessed though.  You could try
"lsof|grep /media/" to see whether something like metalayer-crawler is
accessing the card.

If the FAT file system on the memory card is corrupted (MicroSoft FAT file
system is so primitive that it can get easily corrupted, but it's needed for
compatibility reasons), it can cause processes to access it constantly, but
usually you should see this in "top".


> wlan0     Link encap:Ethernet  HWaddr 00:1D:6E:9B:D8:F6  
[...] 
> though wifi was off

If you want Wifi off (instead of just not connected to some specific access
point), use the "offline" mode listed in the Power (button) menu.  This will
turn off also other radios. I think Diablo has more(?) online activities than
older releases, so the effect of this is larger.

The interval how often network should be used to concerve power, is *much*
larger than for CPU which can sleep & wake up almost instantly.

I always set my own device offline when not using net as I just need to press
OK in a dialog when net is needed again and re-connecting takes only a few
secs.


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